8.1. The essence and objectives of the course "Digital Cartography"
The course "Digital Cartography" is an integral part of cartography. He studies and develops the theory and methods for creating digital and electronic maps, as well as the automation of cartographic work.
Cartography has now moved to a new qualitative level. In connection with the development of computerization, many processes for creating maps have completely changed. New methods, technologies and directions of mapping have appeared. It is possible to single out various areas that cartography is engaged in today: digital mapping, three-dimensional modeling, computer publishing systems, etc. In this regard, new cartographic works have appeared: digital, (electronic and virtual) maps, animations, three-dimensional cartographic models, digital models terrain. In addition to creating computer maps, the task is to form and maintain databases of digital cartographic information.
Digital cards are inseparable from traditional cards. Theoretical basis cartographies accumulated over the centuries have remained the same, only the technical means of creating maps have changed. Usage computer technology led to significant changes in the technology of creating cartographic products. The technology for performing graphic works has been greatly simplified: labor-intensive drawing, engraving and other handmade. As a result, all traditional drawing materials and accessories fell into disuse. A cartographer who knows the software can quickly and efficiently perform complex cartographic work. There are also many opportunities to perform design work at a very high level: the design of thematic maps, covers of atlases, title pages, etc.
With the introduction of computer technology, the processes of compiling and preparing maps for publication were combined. There is no need to make a high-quality manual copy of the original (publishing original). A design original made on a computer makes it very easy to edit and correct proofreading notes without compromising its quality.
The advantages of computer technology are not only the ideal quality of graphic works, but also high accuracy, a significant increase in labor productivity, and an increase in the printing quality of cartographic products.
8.2. Definitions of digital and electronic cartographic works
The first work on the creation of digital maps was started in our country in the late 70s. At present, digital maps and plans are mainly created from traditional original maps and plans, drafting originals, circulation prints and other cartographic materials.
Digital maps are digital models of objects presented as numerically encoded plan coordinates x and y and an applicate z .
Digital maps are logical and mathematical descriptions (representations) of mapped objects and relations between them (relationships of terrain objects in the form of their combinations, intersections, neighborhoods, height differences in relief, orientation to the cardinal points, etc.) formed in the coordinates accepted for conventional maps , projections, systems of conventional signs, taking into account the rules of generalization and requirements for accuracy. Like ordinary maps, they differ in scale, subject matter, spatial coverage, etc.
The main purpose of digital maps is to serve as the basis for the formation of databases and automatic compilation, analysis, and transformation of maps.
In terms of content, projection, coordinate system and heights, accuracy and layout, digital maps and plans must fully meet the requirements for traditional maps and plans. On all digital maps, topological relationships between objects must be observed. There are several definitions of digital and electronic maps in the literature. Some of them are shown in this topic.
A digital map is a representation of map objects in a form that allows a computer to store, manipulate, and display the value of their attributes.
A digital map is a database or file that becomes a map when a GIS creates a hard copy or an image on the screen (W. Huxhold).
Electronic cards- these are digital maps visualized in a computer environment using software and hardware, in accepted projections, systems of conventional signs, subject to the established accuracy and design rules.
Electronic atlases- computer analogues of conventional atlases.
Capital atlases are created by traditional methods for a very long time, tens of years. Therefore, very often, even in the process of creation, their content becomes outdated. Electronic atlases can significantly reduce the time of their production. Maintaining electronic maps and atlases up to date, updating them is currently being done very quickly and efficiently.
There are several types of electronic atlases:
Atlases for visual viewing only ("flipping") - viewer atlases.
Interactive atlases, in which you can change the design, image methods and classification of mapped phenomena, get paper copies of maps.
Analytical atlases(GIS-atlases), which allow you to combine and compare maps, conduct their quantitative analysis and evaluation, and overlay maps on top of each other.
In many countries, including Russia, National Atlases have been created and are being created. The national atlas of Russia is official government publication created on behalf of the Government Russian Federation. The National Atlas of Russia provides a comprehensive picture of nature, population, economy, ecology, history and culture of the country (Fig. 8.1). The atlas consists of four volumes: volume 1 - " general characteristics territory"; volume 2 - “Nature. Ecology"; volume 3 - “Population. Economy"; volume 4 - “History. Culture.
Rice. 8.1. National Atlas of Russia
The atlas is issued in printing and electronic forms(the first three volumes, the electronic version of the fourth volume will be released in 2010).
Cartographic Animations- dynamic sequences of electronic maps that convey on the computer screen the dynamics and movement of depicted objects and phenomena in time and space (for example, the movement of precipitation,
movement of vehicles, etc.).
We often have to observe animations in everyday life, for example, television weather forecast maps, on which the movements of fronts, areas of high and low pressure, and precipitation are clearly visible.
To create animations, various sources are used: remote sensing data, economic and statistical data, data from direct field observations (for example, various descriptions, geological profiles, observations of weather stations, census materials, etc.). Dynamic (moving) images of cartographic objects can be different:
− moving the entire map on the screen and individual elements of the content on the map;
− change appearance conventional signs (size, color, shape, brightness, internal structure). For example, settlements can be shown as pulsating punches, etc.;
− cartoon sequences frame maps or 3D images. This way it is possible to show the dynamics of glacier melting, the dynamics of the development of erosion processes;
− panning, rotation of computer images;
− scaling the image, using the effect of "influx" or removing the object;
− creating the effect of movement over the map (flying around, detour of the territory).
Animations can be flat and three-dimensional, stereoscopic and, in addition, can be combined with a photo image.
Three-dimensional animations combined with a photographic image are called virtual
maps (creates the illusion of a real area).
Technologies for creating virtual images can be different. As a rule, first a digital model is created based on a topographic map, aerial or satellite image, then a three-dimensional image of the area is created. It is painted in the colors of the hypsometric scale and then used as a real model.
8.3. The concept of geographic information systems (GIS)
The first geographic information systems were created in Canada, the USA and Sweden to study natural resources. The first GIS appeared in the early 60s. In Canada. The main goal of the Canadian GIS was the task of analyzing the land inventory data of Canada. In our country, such studies began twenty years later. Currently, in many countries there are various geographic information systems that solve a variety of tasks in various industries: in the economy, politics, ecology, cadastre, science, etc.
In the domestic scientific literature, there are dozens of definitions of GIS.
Geographic Information Systems (GIS) – hardware and software com-
complexes providing collection, processing, display and distribution of space
vein-coordinated data (A.M. Berlyant). One of the functions of GIS is the creation and use of computer (electronic) maps, atlases and other cartographic products.
Geographic information system is an information system designed to collect, store, process, display and distribute data, as well as receive
based on them new information and knowledge about spatially coordinated objects and phenomena.
The essence of any GIS is that it is used to collect, analyze, organize, store various information, create a database. The most convenient form of presenting information to users is cartographic images, in addition, information can also be presented in the form of tables, diagrams, graphs, texts.
A distinctive feature of GIS is that all information in them is presented in the form of electronic maps that contain information about objects, as well as spatial reference of objects and phenomena. Electronic maps differ from paper maps in that each conventional sign (object) depicted on an electronic map corresponds to the information entered in the database. This allows you to analyze them in relation to other objects. By pointing the mouse cursor, for example, at any region, you can get all the information entered into the database about it (Fig. 8.2).
Rice. 8.2. Getting information about an object from the database
In addition, geographic information systems work with cartographic projections, which allows for projection transformations of digital and electronic maps.
Rice. 8.3. Selecting a Map Projection in GIS MapInfo Professional
At present, specialized land geoinformation systems, cadastral, ecological and many other GIS have been created.
On the example of the administrative map of the Tomsk region, let's consider the possibilities of GIS. We have a database that contains information about the size of the area of the districts of the Tomsk region and the number of inhabitants in each district (Fig. 8.4). Based on these data, we can obtain information about the population density of the Tomsk region, in addition, the program builds a population density map (Fig. 8.5).
Rice. 8.4. Creation of a thematic map based on the data entered in the database
Rice. 8.5. Population density map of the Tomsk region, built in automatic mode
In this way, distinctive features GIS are:
− geographic (spatial) data referencing;
− storage, manipulation and management of information in the database;
− opportunities to work with projections of geographic information;
− obtaining new information based on existing data;
− reflection of spatio-temporal relations between objects;
− the ability to quickly update databases;
− digital terrain modeling;
− visualization and data output.
8.3.1. GIS subsystems
GIS consists of a number of blocks, the most important of which are input, processing block
and information output (Fig. 8.6).
Rice. 8.6. GIS structure
Information input block includes the collection of data (texts, maps, photographs, etc.) and devices for converting information into digital form and entering it into computer memory or into a database. Previously, special digitizer devices were widely used for this purpose - devices with manual tracing of objects and automatic registration of their coordinates. They have now been completely replaced. automatic devices- scanners. The scanned image is digitized using special software. All characteristics of digitized objects, including statistical data, are entered from the computer keyboard. All digital information enters the database.
A database is a collection of information organized in such a way that it can be stored on a computer.
Formation of databases, access and work with them provides database management system (DBMS), which allows you to quickly find the required information and carry out its further processing.
Sets of databases and means of managing them form databanks.
Information processing unit includes the use of various software that allows you to bind a raster image to a specific coordinate system, select the desired projection, perform automatic generalization of content elements, convert a raster image into a vector image, select image methods, build thematic and topographic maps, combine them with each other, as well as to design cartographic works.
Information output block- includes devices that allow you to display mapping results, as well as texts, tables, graphs, diagrams, three-dimensional images, etc. These are screens (displays), printing devices (printers), plotters, etc.
GIS for production purposes also includes a subsystem for issuing maps, which allows you to make printing forms and print the circulation of maps.
8.3.2. Organization of data in GIS
The data used in GIS can be very different: the results of geodetic and astronomical observations, data from field observations (geological profiles, soil sections, census materials, etc.), various maps, images, statistical data, etc.
Data in GIS has a layered organization, i.e., information about objects of the same thematic content is stored in one layer (hydrography, relief, roads, etc.).
Thus, a GIS map consists of a set of information layers (Fig. 8.7). Each layer contains different types information: areas, points, lines, texts, and together they make up a map.
The distribution of objects by layers allows you to quickly edit objects, work with queries, and make various changes. Layers on the map can be managed: swapped, turn off visibility, block, freeze, delete, etc.
When designing a digital map, the layers must be arranged in a certain sequence, so when creating a new layer, it is placed in a certain place. The layers of background elements must be placed below the layers of stroke elements so that they do not cover the image. The sequence of layer placement conveys the correctness of the overlay of dashed and background elements of the map.
The number of layers for each map can be different and depends on the purpose of the map and the tasks that will be solved on this map. A very important task is the correct composition of layers and the distribution of objects by layers. It should be remembered that a large number of layers can make it difficult to work with the map.
Digital Cartography and GIS
In the last decade, cartography has been undergoing a period of profound changes and technological innovations caused by the informatization of science, industry and society as a whole. There was a need to revise and redefine many concepts of this scientific discipline. For example, back in 1987, two working groups on cartographic definitions and concepts were established within the International Cartographic Association. Moreover, one of the main questions to be studied and resolved was the question of whether it is possible to define cartography without the concept of "map" and whether GIS or its elements should be included in this definition. In 1989. The working group proposed the following definition: "Cartography is the organization and communication of geographically referenced information in graphical or digital form; it may include all stages from collection to display and use of data." The concept of "map" is not included in this definition, but it is proposed to consider it separately as a "holic (i.e., holistic, structural) display and mental abstraction of geographical reality, intended for one or more purposes and transforming the corresponding geographical data into works presented in visual, digital or tactile forms".
These definitions have sparked a lot of discussion among cartographers, and as a result, an alternative definition of cartography has emerged, in which it is considered as "the organization, display, communication and use of spatially coordinated information presented in graphic, digital and tactile forms; may include all stages from data collection prior to their use in creating maps or other spatial information documents.
According to most modern cartographers, the technological aspects of cartography are not the main ones in the era of computer science, and all definitions of cartography through technology are erroneous. Cartography remains an applied, predominantly visual discipline in which communication aspects are of great importance. The assessment of computer maps in the sense of their similarity, indistinguishability from manually created maps is also erroneous. The real value of GIS technology lies precisely in the possibility of creating works of a new type. With all this, the main task of cartography remains the knowledge of the real world, and here it is very difficult to separate the form (cartographic display) from the content (reflected reality). The progress of geoinformation technologies has only increased the range of data to be mapped, expanded the range of scientific disciplines in need of cartography. Screen (display) maps and electronic atlases, which are now becoming part of national cartographic programs in many countries, only strengthen the links between cartography and computer graphics and GIS, without changing, however, the essence of cartography.
It should be noted that digital cartography in genetic terms is not a direct continuation of traditional (paper) cartography. It has evolved in the course of the overall development of GIS software and is therefore often viewed as a minor GIS component that, unlike GIS software, does not require a large investment of effort and resources. So, an untrained user with the help of existing GIS software after a few days of training can already create a simple digital map, but even in a month he is not able to create a workable GIS software. On the other hand, as cartographers note, due to the apparent ease and simplicity, digital cartography is underestimated with all the ensuing consequences.
Digital cartography came to life own life and its association with traditional cartography is often seen as completely superfluous. As you know, the creation of a traditional paper map requires rather complex equipment, as well as a team of experienced specialists (cartographers-designers) who create and edit maps and perform routine work on processing primary material. This is a technically and technologically very complex and time-consuming process. On the other hand, to create a digital map, you only need a personal computer, external devices, software, and the original (generally paper) map. In other words, any user gets the opportunity to create digital maps in the form finished products- digital cards for sale. As a result, a lot of non-professionals are currently engaged in digital mapping, and the separation from the theory and methodology of traditional cartography leads to a loss in the quality of the transfer of geometric and topological forms of map objects, because the ability to draw well on paper is not enough for high-quality digitization (digitization is a more complicated process, since how one has to qualitatively approximate continuous curves by line segments). At the same time, the quality of design also suffers: often printed maps "resemble a certain drawing with a set of color spots, but not a map at all."
Only recently, with the development of the GIS market, the need for high-quality digital maps has begun to increase; users began to pay attention not only to the speed of digitizing maps and their low price, but also to the quality. The number of places where specialists are trained using GIS technology is growing; Western systems are being Russified and Ukrainianized, expanding the range of potential GIS users. Thus, there is a tendency for the qualitative development of digital cartography in the wake of the overall development of GIS technology.
Let's consider some features of digital mapping technology and the main parameters of digital maps. First of all, it should be noted that due to the variety of tasks solved with the help of digital maps, it is difficult to unambiguously determine the universal criteria for their quality, so the most general criterion should be the ability to provide a solution to the problem. At the moment, the situation on the market of digital maps is such that they are mainly created for a specific project, in contrast to traditional cartography, where already existing cartographic materials are used as a base map. Therefore, most often the creation of a digital map is determined not by well-established and time-tested instructions, but by scattered and not always professionally drawn up technical specifications.
Digital map quality
The quality of a digital map consists of a number of components, but the main ones are information content, accuracy, completeness and correctness of the internal structure.
Informativeness. A map as a model of reality has epistemological properties, for example, such as meaningful correspondence (scientifically based display of the main features of reality), abstractness (generalization, the transition from individual to collective concepts, the selection of typical characteristics of objects and the elimination of secondary ones), spatio-temporal similarity (geometric similarity of sizes and shapes, temporal similarity and similarity of relationships, connections, subordination of objects), selectivity and syntheticity (separate representation of jointly manifesting phenomena and factors, as well as a single holistic image of phenomena and processes that manifest themselves separately in real conditions). These properties, of course, also affect the quality of the final product - a digital map, but mainly belong to the competence of the creators of the original cartographic work: the creators of a traditional source map are responsible for its information content, and when creating a digital map, it is important to choose the right source and correctly convey , taking into account the features of digital mapping, the information embedded in the original map.
completeness Content transfers. The value of this parameter depends mainly on the technology of creating a digital map, i.e., on how strictly the control of passes by operators of digitization objects is carried out. For control, a hard copy of a digital map printed on plastic in the scale of the original can be used. In the subsequent imposition on the source of digitization, the contents of the digital map and the source material are verified. This method can also be used to assess the quality of the transfer of object shapes, but it is unacceptable for assessing the error in the position of the contours, since the output device always gives noticeable distortion. When vectorizing a raster, combining the layers of the created digital map and the raster substrate allows you to quickly identify missed objects.
Accuracy. The concept of digital map accuracy includes such parameters as the error in the position of the contours relative to the source, the accuracy of transferring the sizes and shapes of objects during digitization, as well as the error in the position of the contours of the digital map relative to the terrain associated with the source of digital mapping (paper deformation, distortion of a raster image during scanning and etc.). In addition, the accuracy depends on the software, the hardware used and the digitization source. At the moment, two technologies for digitizing maps exist in parallel and complement each other - digitizer input and digitization by raster (scanning). Practice shows that now it is difficult to talk about the advantage of any one of them. With digitizing digitization, the main amount of work on entering digital maps is performed by the operator in manual mode, i.e., to enter an object, the operator points the cursor at each selected point and presses the button. The accuracy of input during digitizing is critically dependent on the qualifications of the operator. When vectorizing raster maps, subjective factors affect less, since the raster substrate allows you to correct the input all the time, however, the transfer of the shape of objects is affected by the quality of the raster, and with jagged edges of the raster line, bends of the drawn vector line begin to appear, which are caused not by the general shape of the line, but by local violations raster.
The correctness of the internal structure.
The finished digital card must have a correct internal structure, determined by the requirements for cards of this type. For example, the core of the cartographic subsystem in a GIS that uses digital vector maps is a multilayer structure of maps (layers), on which end-to-end search operations, overlay operations with the creation of derivative digital maps and maintaining the connection of object identifiers of source and derived maps must be performed. To support these operations, the topological structure of digital maps in GIS is subject to requirements that are much more stringent than, for example, maps that are used to solve problems of automated mapping or navigation. This is due to the fact that the contours of objects from different maps (layers) must be strictly consistent, although in practice, despite the sufficiently accurate digitization of the source maps separately, this agreement is not achieved, and when digital maps are superimposed, false polygons and arcs are formed. Mismatches can be visually indistinguishable up to a certain magnification scale, which is quite acceptable for automated mapping tasks focused on creating traditional fixed-scale maps using a computer. However, this is completely unacceptable for the functioning of a GIS, when a strict mathematical apparatus is used to solve various problems of analysis. For example, a topological map must have a correct line-nodal (polygons must be assembled from arcs, arcs must be connected at nodes, etc.) and multilayer structure (corresponding boundaries from different layers coincide, the arcs of one layer are exactly adjacent to the objects of another, etc. e). Creating the correct structure of a digital map depends on the capabilities of the software and on the technology of digitization.
At present, a whole industry of digital mapping has already been formed in the world, an extensive market for digital maps and atlases has developed. The first successful commercial project here, apparently, should be considered the Digital Atlas of the World (manufactured by Delorme Mapping Systems), released in 1988. This was followed by the British Domesday Project /100/, as a result of which a digital atlas of Great Britain was created on optical disks (military topographic survey materials were used as source maps and topographic bases). Since 1992, the US Department of Defense Mapping Agency has been producing and updating the Digital Chart of the World (DCW) at a scale of 1:1,000,000. In many countries of the world, national digital atlases and general geographic maps have already been created. On Fig. 5.1 shows a black-and-white printout of one of the fragments of the digital atlas of the world.
Digital cartography - 3.7 out of 5 based on 6 votes
Digital maps can be directly perceived by a person when visualizing electronic maps (on video screens) and computer maps (on a solid basis), and can be used as a source of information in machine calculations without visualization in the form of an image.
Digital maps serve as the basis for the production of conventional paper and computer maps on a solid substrate.
Creation
Digital maps are created in the following ways or a combination of them (in fact, methods for collecting spatial information):
Digitization (digitization) of traditional analogue cartographic products (for example, paper maps);
photogrammetric processing of remote sensing data;
Field survey (for example, geodetic tacheometric survey or survey using global satellite positioning systems instruments);
· cameral processing of data from field surveys and other methods.
Storage and transmission methods
Since the models describing space (digital maps) are very non-trivial (unlike, for example, raster images), specialized databases (DB, see spatial database) are often used for their storage, rather than single files of a given format.
To exchange digital cards between different information systems, special exchange formats are used. These can be either popular formats of some software (software) manufacturers (for example, DXF, MIF, SHP, etc.), which have become a de facto standard, or international standards (for example, such a standard of the Open Geospatial Consortium (OGC) like GML).
Cartography
Cartography (from the Greek χάρτης - papyrus paper, and γράφειν - to draw) is the science of researching, modeling and displaying the spatial arrangement, combination and interconnection of objects, natural phenomena and society. In a broader interpretation, cartography includes technology and production activities.
The objects of cartography are the Earth, celestial bodies, the starry sky and the Universe. The most popular fruits of cartography are figurative-sign models of space in the form of: flat maps, relief and volumetric maps, globes. They can be presented on solid, flat or voluminous materials (paper, plastic) or as an image on a video monitor.
Sections of cartography
Mathematical cartography
Mathematical cartography is the study of ways to display the surface of the Earth on a plane. Since the surface of the Earth (approximately spherical, which is often described by the concept of an earth spheroid) has a certain curvature that is not equal to infinity, it cannot be displayed on a plane with the preservation of all spatial relationships simultaneously: angles between directions, distances and areas. You can save only some of these ratios. An important concept in mathematical cartography is cartographic projection, a function that specifies the transformation of the spheroid coordinates of a point (that is, coordinates on the earth's spheroid, expressed in angular measure) into flat rectangular coordinates in one or another cartographic projection (in other words, into a map sheet that can be spread out in front of you on the surface of the table). Another significant branch of mathematical cartography is cartometry, which allows using map data to measure distances, angles and areas on the real surface of the Earth.
Drawing up and designing maps
Drawing up and designing maps is a field of cartography, a field of technical design that studies the most adequate ways of displaying cartographic information. This area of cartography is closely interconnected with the psychology of perception, semiotics and similar humanitarian aspects.
Since the maps display information related to a wide variety of sciences, there are also such sections of cartography as historical cartography, geological cartography, economic cartography, soil cartography, and others. These sections relate to cartography only as a method; in terms of content, they relate to the corresponding sciences.
Digital cartography
Digital (computer) cartography is not so much an independent section of cartography as its tool, due to state of the art technology development. For example, without canceling the methods of recalculating coordinates when displaying the Earth's surface on a plane (it is studied in such a fundamental section as mathematical cartography), digital cartography has changed the ways of visualizing cartographic works (it is studied in the section "Compilation and design of maps").
So, if earlier the author's original map was drawn in ink, today it is drawn on the computer monitor screen. To do this, use Automated Cartographic Systems (ACS), created on the basis of a special class of software (SW). For example, GeoMedia, Intergraph MGE, ESRI ArcGIS, EasyTrace, Panorama, Mapinfo, etc.
At the same time, ACS and Geographic Information Systems (GIS) should not be confused, since their tasks are different. However, in practice, the same set of software is an integrated package used to build both ACN and GIS (bright examples are ArcGIS, GeoMedia and MGE).
Creation of electronic maps (contours) of fields.
For effective management It will not be superfluous for an agricultural enterprise to know exactly what acreage you have. It is not uncommon for managers and agronomists of farms to know only approximately the size of their fields, which negatively affects the accuracy of calculating the necessary fertilizers and calculating the yield. Using a GPS receiver, a field computer and special software (software), you can get electronic maps (contours) of fields with centimeter accuracy!
Resource-saving technologies, including precision agriculture, involve working with electronic field maps. This is the geoinformation base on the basis of which almost all agrotechnical operations in precision farming are carried out. For example, one of the most complex agrotechnical operations of precision farming - differentiated application of mineral fertilizers is based on maps of the distribution of nutrients (N, P, K, Humus, ph) across the field. For this, an agrochemical survey of farmland is also carried out.
But even if electronic field maps are not used for further application of precision farming technologies, the benefits of creating such maps are obvious. Knowing the exact areas of your fields and the distances between them, you can more efficiently and rationally:
1. Calculate the amount of necessary fertilizers and agrochemicals, as well as seed material
2. Take into account the resulting yield
3. Calculate the planned consumption of fuel and lubricants
4. Keep annual records of sown areas with high accuracy for each crop
5. Keep a history of fields (crop rotations)
6. If necessary, prepare visual reports high precision(card printing)
The creation of field contours is carried out using a GPS receiver, a field computer and software combined into a single software and hardware complex. In the "polygon" mode, it is necessary to go around or bypass the field along its border and save the resulting contour. When saving, you can specify the name of the field and other necessary attributes and notes. After saving the contour, we will know the exact area of the field.
The software also allows you to apply other geoinformation information: lines and points. Lines can be operated when marking working areas in the fields. For example, if you already have electronic maps of your fields for the past year and you only need to fix the placement of crops in the fields this year, then there is no need to re-outline the fields. It is only necessary to draw demarcation lines between crops, and then only if two or more crops are cultivated on the same field.
Points are used to map field features such as pillars, large rocks, and so on.
All received geoinformation from the software and hardware complex must be transferred to a stationary computer for further analysis and use in calculations and in making management decisions. Geoinformation software (GIS) must also be installed on a stationary computer, which will allow you to work correctly with the information received in the fields. For these purposes, we recommend using the MapInfo © program.
In principle, you can use any GIS system that works with the .SHP (Shape) format. Almost all GIS systems can work correctly with this format. However, MapInfo © is, in our opinion, the best choice for accounting for acreage and field history. in mapinfo. You can create thematic maps, superimpose the contours of your fields on satellite and aerial photographs, as well as on digitized topographic maps. Also in MapInfo there is a handy tool for measuring distances (for example, to measure the distance from the garage to the field).
Nowadays, a very high level of automation prevails, and this is reflected in almost all areas of human activity. In connection with such relevance of technical progress, digital cartography arose, which is a computer processing and analysis of cartographic information. On the this moment it is digital cartography that is the most popular in its scientific field, since now the creation of any cartographic images is performed on a computer.
Digital cartography cannot be called a separate discipline or section. This is most likely effective tool, which allows you to conveniently and quickly process cartographic data using a PC. However, the influence of digital cartography on science is really strong, and this way of displaying the terrain has fundamentally changed the principle of territory visualization.
Let's compare digital cartography with the old way of creating maps. In ancient times, cartographers spent days and nights at the map, drawing each element in ink. Such work was very painstaking, and the labor costs were simply unjustified. Now the technology for creating maps has changed significantly, and now the computer does all the routine work, and much faster. During the processing of cartographic information on a PC, special automated systems, which have a lot of functionality, consisting of the tools needed to create maps. Due to their flexibility, automated mapping systems provide a lot of opportunities for modern cartographers, which really simplify and improve the process of illustrating the area.
This wording of the legendary Captain Vrungel, magnificent in brevity and capacity, fully reveals the tasks solved by navigators with the help of navigation in navigation, regardless of where they pass - on the lake, in the sea or in the ocean.
For several millennia, the compass, map, and sextant have been the main navigational instruments. Having reached perfection in the course of development, these three whales, on which navigation was based, nevertheless became an obstacle to technical progress in navigation. The increased size and speed of ships, the increase in the intensity of navigation required the introduction of new navigation technologies, automation of navigation, and increased safety of ships. The traditional tools of the shipmaster could not meet these requirements.
In order to overcome the impasse, a qualitative leap in cartography was required - and it happened at the end of the last century. New high-performance computers made it possible to digitize paper maps, store them, record them on compact media, transmit over communication lines, and restore them again on computer displays.
The pinnacle of modern navigation and computer technologies was the creation of the brain of a modern vessel - the electronic cartographic information system ECDIS, which displays maps and the position of the vessel, plots a route and controls deviations from a given route, calculates safe courses, warns the navigator about danger, maintains a ship's log, and controls the autopilot etc.
A modern electronic cartographic system consists of three main elements - digital maps recorded on any media (mainly on CDs), a GPS receiver and a computer with an appropriate software. Such a system is used on large vessels of the professional fleet, but on small vessels - boats, motor and sailing yachts, small fishing boats - its use is associated with great difficulties, usually due to lack of space and the need to protect the computer from water, moisture, sea salt . Therefore, special devices with different names were created for the small fleet - chartplotters, navigation and cartographic systems, navigation centers containing a GPS receiver in their sealed case, a computer with a program installed at the factory and a miniature carrier of cartographic information (cartridge).
Consider the individual elements of the navigation and cartographic system of a small vessel.
Cartographic information carriers for navigation systems of small craft (chartplotters) are mini-cartridges. If the world database of electronic maps is usually recorded on laser compact discs, then a set of maps of various scales of individual regions is recorded on mini-cartridges. The number of writable cards depends on the capacity of the cartridge. So, for example, one C-Map NT+ cartridge can contain a set of maps of the Azov and Black Seas.
There are several electronic chart systems used to record charts on cartridges: C-Mar NT+, Navionics Nav-Charts™, Furuno MiniChart and some others. The collection of C-Map NT+ cartridges has the greatest coverage of the World Ocean, and, most importantly, it includes electronic maps of domestic regions: Ladoga and Onega lakes, the Gulf of Finland, the Barents, White, Azov, Black and Caspian seas, water areas adjacent to Far East coast of Russia. Therefore, in the future, we will talk about equipment that works with electronic maps in the C-Map NT + format. C-Map NT+ cartridges are manufactured by the international company C-MAP, whose representative in Russia is C-MAP Russia.
There are cartridges suitable for short "recreational" trips (Local), there are those that are used for transitions to medium distances (Standard), and there are cartridges designed for long trips (Wide). For example, if one S (Standard) cartridge contains maps of Onega or Ladoga lakes, then the cartridge contains
W (Wide) includes simultaneously maps of both lakes and the eastern part of the Gulf of Finland. Especially for fishermen, cartridges have been released that include bathymetric data. Most C-MAP NT+ cartridges contain port and tide information that can be displayed by the user on the plotter display. One cartridge can contain more than 150 electronic navigational charts and port plans of various scales from 1:1500000 to 1:1500.
A special user cartridge (USER C-Card) will allow you to record the coordinates of any points that you may need on your next trip, whether it's a restaurant on the coast or a place for scuba diving.
If you want to work on the path you have traveled or plan your future route while at home, you can use PC Planner NT. This instrument is designed to use a personal computer (PC) as a navigational planning tool. The PC display screen shows the available electronic charts using C-MAP NT+ cartridges, which are used directly on board the vessel. The functions of PC Planer NT are map viewing, zooming, creating custom marks, route planning, viewing the distance traveled. Every planning function on a chart plotter can be just as easily implemented on a home computer.
C-MAP electronic chart data sources are official charts produced by hydrographic offices, own production data under contracts with hydrographic services, digitization of survey materials of small harbors in the absence of official paper maps (by order of local authorities).
The NT cartographic database is subject to regular updates based on notices from mariners. New releases of the NT database are made three times a year. The user can exchange an old cartridge for a corrected one (as well as purchase a new one) simply by contacting the S-MAR Russia office or one of the dealers.
CHARTPLOTTER
A chartplotter (or navigation center) is a functionally complete device containing in its waterproof housing a GPS receiver (in some models, the receiver may be remote), a computer with a factory-loaded program, a monochrome or color display, a keyboard for control and a slot for cartridge entry. Some models do not have a GPS receiver, and information about their own coordinates comes from external source. A mandatory element is a port for input-output of information in the international maritime format NMEA 0183.
With work and characteristic features Let's get acquainted with chartplotters on the example of a popular model - Raychart 520 with a monochrome display or its analogue Raychart 530 with a color display manufactured by the famous English company Raymarine.
Both chartplotters have a 12-channel parallel GPS receiver combined with an antenna. The receiver has all the necessary functions: determination of coordinates and movement parameters, the ability to create and store waypoints and movement routes along them, and graphic display tools.
To facilitate the work with chartplotters, a world map with all major ports and settlements is pre-installed in them at the factory. It does not contain detailed information inherent in a sea chart, so it can only be used where it is known that there are no navigational hazards.
Detailed maps of a particular area (eg, Lake Onega, Black Sea) are entered from the cartridge, for which the chartplotter has one or two slots.
WORKING WITH THE CHARTPLOTTER
Turn on the receiver by pressing the POWER key. One more press of this key - and the backlight brightness and image contrast controls appear on the screen, allowing you to adjust the image quality.
Almost all chartplotters are controlled in the same way as in a computer, through the menu, or using the trackball and function keys. Using the menu, set the necessary settings for the display, track, units of measure, guard zones, etc., select various functions, create routes and waypoints.
After turning on the device, as soon as its GPS receiver acquires satellite signals, a map of the vessel's location area will be installed on the screen, the image of which will be located in the center. If there is a cartridge for this area, then the screen will display detailed map specific area.
Vessel movement is shown on the display in one of two ways. In the first case, its mark remains stationary in the center of the screen against the background of a moving map, in the second case, the mark moves from the center to the edge of the screen and, upon reaching it, returns back simultaneously with the map shift. If necessary, the trajectory of the vessel's movement and its current coordinates can be displayed.
Cursor usage
The cursor plays an important role in working with the chartplotter. With its help, many tasks are solved: measuring the azimuth and range to objects, determining their coordinates, creating waypoints and routes, obtaining information, and much more. Let's take a look at a few cursor functions as an example.
If during navigation it becomes necessary to determine the distance to some object on the map (banks, landmarks), it is enough to move the cursor over this point, and its coordinates will appear in the information window, as well as the range and direction relative to the vessel. Similarly, using the cursor, information is obtained about the names of islands marked on the map, settlements, ports, navigation conditions, depths, etc.
Using the cursor makes creating waypoints and routes much easier. Unlike a GPS receiver, where this task is solved using a paper map with further input of the received coordinates through the menu, in a chartplotter this is simply and quickly done using the cursor: just place it on the right place on the electronic map and press the desired key. The resulting waypoint can then be easily edited, given a symbol or name, moved to another location, or deleted.
A route is created in a similar way: its number is assigned, and points are sequentially applied to the map on the screen with the cursor, which determine the route of the vessel. The results of laying will remain on the map in the form of a broken line, which can be corrected during preparation and during navigation by moving, adding or deleting points with the cursor.
The received routes and their constituent points are placed on special pages in the form of tables with coordinates. You can rename them, assign symbols (for example, anchor, cross, fish, etc.), change coordinates, delete, and you can do this not only in swimming, but also at home, using the simulation mode for this.
Sailing along the route By "navigating along the route" we will understand the sequential movement from point to point of a pre-planned and stored route using the technical and software capabilities of devices that allow controlling the ship's deviations from a given direction.
In modern chartplotters, when sailing along a route, deviation control is carried out in two ways: either by the position of the ship’s mark on the laid route, or using special graphic indicators, usually used in GPS receivers - “highway” (“road”), “compass”, “ route". Some chartplotter models can combine both modes on the same screen, making it easier to navigate in difficult navigational environments. In addition, graphic indicators allow you to use the device as a conventional GPS receiver in places where C-Map NT maps are not available.
If the route is created in advance and stored in the instrument's memory, then through the menu you enter the route library, find the desired one and activate it using one of the available methods, after which the map section with the route is displayed on the screen and the chartplotter switches to navigation mode. In this case, the data window will show the direction to the first waypoint of the route, the distance to it, the travel time and the time of arrival, and the graphic displays will show deviations from the true course. Upon arrival at the first point, the device will automatically switch to the mode of movement to the next point, and so on, until the arrival at the final point of navigation. Approaching a point at a certain distance can optionally be accompanied by a sound signal simultaneously with the appearance of a message in the information window on the screen.
Waypoint navigation
Waypoint navigation is a special case of route navigation, so the principles of using a chartplotter and navigation are the same.
Waypoints can be created in advance and stored in the unit's memory, from where they can be retrieved, activated with the GO TO function, and used for navigation. Creating waypoints while sailing is very efficient with the cursor: just move the cursor to the desired location and press the GO TO key, and the chartplotter will navigate to the selected waypoint.
SERVICE FUNCTIONS
Information database
Each chartplotter contains a set of information data, the volume and content of which may vary from model to model. Part of the information base is introduced during the production of devices, and the main part comes along with the electronic map of the area.
The main part of the database is navigation information, which is always present in every chartplotter. This includes information about depths, navigational hazards, navigational conditions, names of islands, bays, ports, etc. Such data is usually displayed automatically in the information window when the cursor is placed on this object or, in some models, when the ship's mark enters the specified area near the object. You can get more if you want. detailed information about the marked object: the height, color and characteristics of the lights of lighthouses and buoys, landmarks, characteristics of navigation areas, information about the presence of bans on swimming and fishing, etc.
The second data block may contain a list of ports and shelters for this map with distances to the ship and directions to them, their characteristics (presence of a telephone and telegraph, hospitals, oil depots, water area features). Often the list of ports is arranged in order of increasing distances to the vessel, which allows, if necessary, to quickly select the nearest shelter.
Custom Functions
Under this not very correct name, we mean a set of a wide variety of functions that make it easier for the user to work with the chartplotter. Each model of the device has its own set of functions, so we will focus only on the most common ones.
MOV ("Man overboard")
This is one of essential functions, which allows you to memorize the place of a person who has fallen overboard with one keystroke and put the chartplotter in navigation mode to the point of impact.
Return to ship function
When laying a route or when viewing a map using the cursor, you can “lose” the mark of the vessel. For a quick return to the place of the vessel, there is a function that can be called “HOME”, “Find ship”, “Ship” or something else in different models. Pressing this softkey quickly displays a section of the chart, in the center of which is the vessel and the cursor.
Track recording
When the vessel is moving, any chartplotter must record and save the route passed. The most sophisticated and expensive instruments can store several traces along with their characteristic features and, if necessary, reproduce them, correct them and use them for navigation.
Navigation alarms
This function allows you to generate alarms (warnings) in cases of entering the established zone, when approaching a waypoint of the route, to navigational danger, when passing over a place where the depth is less than the specified one, when the ship is drifting at anchor.
Map catalogs
Some expensive chartplotters often include chart catalogs that make it easy to find or order the right cartridge while cruising. The catalog of maps can be both for the region and the world.
"Echo sounder"
This feature, available on some chartplotters, allows you to read the current depth values from the chart and display them simultaneously with the chart on the screen in digital or graphical form.
The modern market offers big choice chartplotters manufactured by various companies, with different screen sizes, color and monochrome, portable and stationary. The appendix provides specifications for some of the most common instruments using C-Map NT and C-Map NT+ cartography. In conclusion, about the paper map. A chartplotter is undoubtedly more convenient than a paper map, it does not wrinkle, does not tear, does not get wet, it is easy to use, it has richer information capabilities. However, the paper chart remains to this day, along with the logbook, the main document of the navigator, which, in the event of an accident, will be dealt with by the competent authorities.
Remember this!
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Characteristics of some electronic chartplotters of various manufacturers |
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| RAYMARINE Raychart 320 |
RAYMARINE Raychart 520 (Raychart 530) |
INTERPHASE Chartmaster 7MX (Chartmaster 7CVX) |
INTERPHASE Chartmaster 11MX (Chartmaster 11CVX) |
FURUNO |
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4,75" |
7" monochrome |
6" monochrome |
10.4" monochrome |
5.6" color |
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| Receiver |
12 channels |
12 channels |
12 channels |
12 channels |
8 channels |
| Waypoints | |||||
| Number of routes | |||||
| Food, V | |||||
| Dimensions, mm | |||||
| Weight, kg | |||||
| Approximate price, c.u. | |||||